Multi-section refractory layer structure of secondary combustion chamber for rotary kiln hazardous waste incineration

Abstract

The invention relates to the technical field of boiler equipment, and discloses a secondary combustion chamber multi-section refractory layer structure for rotary kiln hazardous waste incineration, which comprises an outer furnace body, and a gas protection assembly for performing gas film soft protection on the inner wall of the equipment is fixedly mounted in the outer furnace body; the gas protection assembly comprises an inner pipe coaxially fixed to the inner wall of the outer furnace body, a smoke exhaust outer pipe is fixedly installed at the position, located above the inner pipe, of the inner wall of the outer furnace body through multiple sets of fixing blocks, and the inner wall of the smoke exhaust outer pipe and the outer wall of a pipe body at the top end of the inner pipe jointly form a first circular seam gas channel. According to the equipment, high-pressure gas is divided and guided to form a first gas film, a second gas film and a third gas film which are tightly attached to corresponding inner walls through the gas inlet ring pipe, the bifurcated pipe, the spraying ring, the flow guide cover, the inner pipe and the smoke exhaust outer pipe, substances are specially prevented from adhering to the inner walls of the equipment, clean protection of the inner walls of the equipment is achieved, faults caused by blockage or corrosion of the substances are reduced, and the service life of the equipment is prolonged. And the overhaul and maintenance frequency is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of boiler equipment, in particular to a multi-section refractory layer structure of a secondary combustion chamber for hazardous waste incineration in a rotary kiln. BACKGROUND

[0002] Biomass fuel heating is an important way of clean energy utilization, and the manufacturing of supporting biomass combustion boilers and related equipment, ovens, furnaces, and electric furnaces is the core of ensuring stable heating. As a key component for treating rotary kiln and boiler tail gas, the secondary combustion chamber plays a role in purifying flue gas and ensuring complete combustion. During operation of the secondary combustion chamber, the rotary kiln and boiler tail gas carry high-corrosive gaseous substances, incompletely combusted solid particles, and ash, which react at high temperatures to form sticky deposits. These deposits are easily adsorbed on the inner wall of the secondary combustion chamber, especially at the kiln opening, necking, inverted cone, and flue corner, and continuously accumulate. The accumulation of deposits can block the flue gas passage and cause uneven airflow, affecting the stability of biomass fuel heating and potentially causing environmental risks. Moreover, the stress of the accumulated material can exacerbate the cracking and spalling of the inner refractory layer. To avoid this problem, regular shutdown and cleaning are required. In the traditional method, after shutdown and cooling, workers open the coke cleaning manhole and manually knock off the deposits using a pneumatic pick, steel pick, or other tools.

[0003] However, the above-mentioned treatment of deposits on the inner wall of the secondary combustion chamber still has the following shortcomings: First, due to the high corrosion of some incineration materials and high working temperature, the inner wall of the secondary combustion chamber is prone to depositing substances. During cleaning, the equipment needs to be shut down, and the internal temperature needs to be reduced to a safe range before the cleaning personnel can manually knock off the deposits using a pneumatic pick, steel pick, or other tools. This manual cleaning method is inefficient and poses safety risks such as high-temperature residues and chemical substance contact. During the hard knocking process, the attached materials, such as aluminum silicate fiber cotton, lightweight insulation material, and ordinary castable refractories, are easily detached from the inner wall, damaging the integrity and sealing insulation of the refractories, causing unevenness in the refractory layer, and further exacerbating the accumulation of sticky deposits, forming a vicious cycle, and ultimately shortening the service life of the equipment. SUMMARY

[0004] The technical problem to be solved by the present application is that the existing deposits on the inner wall of the secondary combustion chamber of the rotary kiln need to be manually cleaned after shutdown and cooling, which is inefficient and poses safety risks. Moreover, the internal refractories are easily damaged and detached, further exacerbating the accumulation and shortening the service life of the equipment. Therefore, we propose a multi-section refractory layer structure of a secondary combustion chamber for hazardous waste incineration in a rotary kiln.

[0005] To achieve the above-mentioned purpose, the following technical solution is adopted: A multi-section refractory layer structure of a secondary combustion chamber for hazardous waste incineration in a rotary kiln, comprising an outer furnace body, wherein a gas protection assembly for soft protection of the inner wall of the equipment is installed and fixed inside the outer furnace body. The gas defense assembly comprises an inner tube coaxially fixed to the inner wall of the outer furnace body, a plurality of groups of fixed blocks are arranged on the inner wall of the outer furnace body and at a position above the inner tube, and an outer smoke exhaust pipe is fixedly installed, the inner wall of the outer smoke exhaust pipe and the outer wall at the top end of the inner tube jointly form a first annular gap air channel, the outer wall of the outer smoke exhaust pipe and the inner wall of the outer furnace body jointly form a second annular gap air channel, the first annular gap air channel and the second annular gap air channel are connected to form an annular pipe air channel, a flow guide cover is fixed to the inner wall of the outer furnace body and below the inner tube, the curved outer wall of the flow guide cover, the inner wall of the outer furnace body and the inner wall of the inner tube jointly form an annular wall air channel, and a spray ring is coaxially fixed to the lower surface of the outer smoke exhaust pipe and at the joint of the first annular gap air channel and the second annular gap air channel. The inner tube is internally provided with a gas guide component for simultaneously supplementing high-pressure gas sources for the annular pipe air channel and the annular wall air channel.

[0006] Preferably, the gas guide component comprises an air inlet annular pipe fixed to the outer wall of the outer furnace body, a plurality of groups of bifurcated pipes are connected to the outer wall of the air inlet annular pipe near the shaft center at equal angles, and the bifurcated pipes penetrate through the outer furnace body and extend to the inside of the inner tube.

[0007] Preferably, one side port of the bifurcated pipe is in communication with the inner cavity of the spray ring, the other side port of the bifurcated pipe is in communication with the annular wall air channel, and the outer wall of the air inlet annular pipe is provided with an air inlet opening in communication with the output end of an external gas supply device.

[0008] Preferably, the inner wall cross section of the inner tube is funnel-shaped, and the outer diameter of the top spray port of the inner tube is smaller than the outer diameter of the outer smoke exhaust pipe.

[0009] Preferably, a plurality of groups of first spiral threads are arranged on the outer wall of the inner tube at equal angles, a plurality of groups of second spiral threads are arranged on the inner wall of the outer smoke exhaust pipe at equal angles, the first spiral threads and the second spiral threads are interpenetrated and staggered, and the outer wall of the top end of the inner tube is in parallel relationship with the inner wall of the outer smoke exhaust pipe.

[0010] Preferably, the top end outer wall of the outer furnace body is provided with a variable diameter section, the variable diameter section comprises a first contraction section, a smooth section and an expansion section, the bottom end of the outer smoke exhaust pipe is provided with a second contraction section, and the first contraction section is in parallel relationship with the second contraction section.

[0011] Preferably, the bottom end outer wall of the flow guide cover is in parallel relationship with the inner wall of the outer furnace body, and the top end annular outer wall of the outer furnace body is in parallel relationship with the top end inner wall of the inner tube.

[0012] Preferably, the opening of the inner wall of the spray ring corresponds to the inclined surface of the second contraction section up and down.

[0013] Preferably, a flange plate is installed on the top end outer wall of the outer smoke exhaust pipe, and the top end outer diameter of the outer smoke exhaust pipe is greater than the top end outer diameter of the outer furnace body.

[0014] Preferably, a side outer wall of the bottom end of the outer furnace body is obliquely provided with a smoke inlet section, and the side outer wall of the bottom end of the outer furnace body is provided with a slag removal opening.

[0015] Technical effects and advantages of the present application: In the present application, the device guides the high-pressure gas to form the first gas film, the second gas film and the third gas film close to the corresponding inner wall through the air inlet ring pipe, the bifurcated pipe, the spray ring, the flow guide cover, the inner pipe and the smoke exhaust outer pipe, specially isolates the adhesion of substances to the inner wall of the device, realizes the clean protection of the inner wall of the device, reduces the failure caused by the blockage or corrosion of the adhesion, and reduces the maintenance frequency.

[0016] In the present application, the device guides the high-pressure gas to form the first gas film, the second gas film and the third gas film close to the corresponding inner wall through the air inlet ring pipe, the bifurcated pipe, the spray ring, the flow guide cover, the inner pipe and the smoke exhaust outer pipe, specially isolates the adhesion of substances to the inner wall of the device, realizes the clean protection of the inner wall of the device, reduces the failure caused by the blockage or corrosion of the adhesion, and reduces the maintenance frequency. BRIEF DESCRIPTION OF DRAWINGS

[0017] The disclosed content of the present application will be explained with reference to the drawings. It should be understood that the drawings are only for illustrative purposes, and are not intended to limit the scope of protection of the present application. In the drawings, the same reference signs are used to refer to the same parts: Figure 1 It is a front view structural schematic diagram of the present application; Figure 2 It is an external overall structural schematic diagram of the present application; Figure 3 It is an external furnace body structural cross-sectional schematic diagram of the present application; Figure 4 It is an external pipe structural cross-sectional schematic diagram of the present application; Figure 5 It is an inner pipe, spray ring and air inlet ring pipe structural cross-sectional schematic diagram of the present application; Figure 6 It is a Figure 5 It is a structure enlarged schematic diagram of A in the present application; Figure 7 It is a flow guide cover structural schematic diagram of the present application; Figure 8 It is a device structural cross-sectional schematic diagram of the present application; Figure 9 It is a device structural plane cross-sectional schematic diagram of the present application.

[0018] Legend: 1, external furnace body; 11, smoke inlet section; 12, slag removal opening; 2, gas protection assembly; 21, inner pipe; 211, first spiral thread; 22, air inlet ring pipe; 221, bifurcated pipe; 23, spray ring; 24, smoke exhaust outer pipe; 241, second spiral thread; 25, flow guide cover. DETAILED DESCRIPTION

[0019] It is easy to understand that, according to the technical solution of the present application, those skilled in the art can propose various structures and implementation modes that can be replaced with each other without changing the essential spirit of the present application. Therefore, the following detailed description and the accompanying drawings are only exemplary descriptions of the technical solution of the present application, and should not be regarded as the whole or as a limitation or restriction on the technical solution of the present application.

[0020] Referring to Figures 1-9 As shown in the drawings, the present application provides a technical solution: a rotary kiln hazardous waste incineration two-burner multi-section refractory layer structure, comprising an outer furnace body 1, the outer wall of the outer furnace body 1 is made of metal material, the inner wall is stacked with refractory material with a thickness of 400mm, which includes aluminum silicate fiber cotton with a thickness of 30mm, light weight insulation material with a thickness of 150mm, and ordinary castable with a thickness of 220mm, which is specially used to deal with incineration materials with high corrosivity and high temperature in the rotary kiln, and to isolate high temperature and various dangerous chemicals, the inner wall of the outer furnace body 1 is fixedly installed with a gas protection assembly 2 for soft protection of the inner wall of the equipment; The gas protection assembly 2 comprises an inner pipe 21 coaxially fixed in the inner wall of the outer furnace body 1, a plurality of fixed blocks are used to fixedly install a smoke exhaust outer pipe 24 on the inner wall of the outer furnace body 1 and above the inner pipe 21, the inner wall of the smoke exhaust outer pipe 24 and the outer wall of the top pipe body of the inner pipe 21 jointly form a first ring gap air channel, the outer wall of the smoke exhaust outer pipe 24 and the inner wall of the outer furnace body 1 jointly form a second ring gap air channel, and the first ring gap air channel and the second ring gap air channel are connected to form a ring pipe air channel, a flow guide cover 25 is fixed on the inner wall of the outer furnace body 1 below the inner pipe 21, and the curved outer wall of the flow guide cover 25, the inner wall of the outer furnace body 1 and the inner pipe 21 jointly form a ring wall air channel, and a spray ring 23 is coaxially fixed on the lower surface of the smoke exhaust outer pipe 24 at the junction of the first ring gap air channel and the second ring gap air channel; The inner pipe 21 is provided with a gas guide component for simultaneously supplementing high-pressure gas sources for the ring pipe air channel and the ring wall air channel.

[0021] The output end of the external gas supply equipment is connected and fixed with the flange plate at the gas inlet of the outer wall of the gas inlet ring pipe 22, the external gas supply equipment is started to inject high-pressure gas into the inside of the gas inlet ring pipe 22, then one of the high-pressure gas streams enters into the spray ring 23 through the one end interface of a plurality of branch pipes 221 and is vertically upwardly sprayed, the high-pressure gas stream is tightly sprayed upwardly along the inner wall of the smoke exhaust outer pipe 24, and is double-limited by the inner wall of the smoke exhaust outer pipe 24 and the outer wall of the inner pipe 21 to form a ring-shaped first gas film, the first gas film can protect the inner wall of the smoke exhaust outer pipe 24, and the continuously sprayed first gas film can block the adhesion of sticky adhesions to keep the inner wall of the smoke exhaust outer pipe 24 relatively clean; Another high-pressure gas flow enters the annular wall gas channel through the other end of the bifurcated pipe 221, and the high-pressure gas flow is dispersed by the impact of the flow guide cover 25 to form two annular gas flows, one of which flows downward and vertically downward along the inner wall of the outer furnace body 1 to form a second gas film, and the other of which flows downward and vertically upward along the inner wall of the inner pipe 21 to form a third gas film. As described above for the first gas film, the second gas film and the third gas film respectively provide gas soft protection for the bottom inner wall of the outer furnace body 1 and the inner wall of the top pipe body of the inner pipe 21, and isolate the viscous attachments; It should be noted that the lower surface of the flow guide cover 25 is provided with a plurality of burners arranged at equal angles, which can maintain the temperature in the second combustion chamber at 1100°C or above, and can inject flame jets to ignite the continuously rising flue gas; The inner wall of the flow guide cover 25 is provided with a plurality of thermal sensing devices arranged at equal angles at the top end position, and the flue gas passes through the inner wall of the flow guide cover 25 for more than two seconds, so as to achieve sufficient combustion of the flue gas. This is a prior art and will not be described in detail; Finally, under the joint impact of the first gas film, the second gas film and the third gas film, the oxygen content in the equipment increases, and the combustion is more complete. Because of the continuous injection of high-pressure and high-speed gas, the gas pressure in the cavity below the inner pipe 21 in the outer furnace body 1 increases. At this time, the high-pressure gas flow carrying the flue gas in the combustion state continuously sprays upward along the inner wall of the flow guide cover 25. At this time, because of the Bernoulli effect, a certain negative pressure is generated at the opening of the second annular gap gas channel; After the equipment runs for a certain period of time, the gas supply rate of the external gas supply equipment can be reduced, and only auxiliary gas flow is provided. At this time, because of the continuous injection of flame jets, a negative pressure is generated above the second annular gap gas channel, and the annular pipe gas channel is a connected structure, so that the external fresh air is continuously sucked in. When the newly entered air reaches the bending position of the annular pipe gas channel, the fresh air is continuously carried upward by the gas flow injected by the external gas supply equipment, thereby realizing the self-circulation of the external gas, and reducing the energy consumption and operation cost of the external gas supply equipment to a certain extent. It should be noted that the annular pipe gas channel is composed of the first annular gap gas channel and the second annular gap gas channel, and the cross-sectional shape is in the shape of the letter U.

[0022] Referring to Figures 3-9 In the embodiment, the gas guide component includes a gas inlet annular pipe 22 fixed to the outer wall of the outer furnace body 1, and a plurality of bifurcated pipes 221 are connected to the outer wall of the gas inlet annular pipe 22 near the axis at equal angles, and the bifurcated pipes 221 penetrate through the outer furnace body 1 and extend into the inner pipe 21.

[0023] The one side port of the bifurcated pipe 221 is communicated with the inner cavity of the spray ring 23, the high pressure gas flow is guided to be sprayed vertically upward through the spray ring 23, the other side port of the bifurcated pipe 221 is communicated with the ring wall gas channel, and the outer wall of the air inlet ring pipe 22 is provided with an air inlet communicated with the output end of the external gas supply device, wherein the air inlet is specifically provided with a flange plate facilitating the butt joint installation with the output end of the external gas supply device.

[0024] Referring to Figures 3-9 In the embodiment, the inner wall of the inner pipe 21 is funnel-shaped, and the outer diameter of the top of the inner pipe 21 is smaller than the outer diameter of the smoke exhaust outer pipe 24.

[0025] The outer wall of the inner pipe 21 is provided with a plurality of groups of first spiral threads 211 at equal angles, the inner wall of the smoke exhaust outer pipe 24 is provided with a plurality of groups of second spiral threads 241 at equal angles, and the first spiral threads 211 and the second spiral threads 241 are interpenetrated and staggered, and the outer wall of the pipe body at the top end of the inner pipe 21 is in parallel relationship with the inner wall of the smoke exhaust outer pipe 24.

[0026] The first spiral threads 211 and the second spiral threads 241 are interpenetrated and staggered to form a plurality of spiral spaces, the first gas film passing through the first annular slit gas channel passes through the plurality of groups of spiral spaces to form a spiral gas flow, thereby further limiting the flow direction and position of the first gas film, so that the first gas film is tightly attached to the inner wall of the smoke exhaust outer pipe 24, and the isolation effect on the viscous adherent is indirectly improved.

[0027] Referring to Figures 1-9 In the embodiment, the top end outer wall of the outer furnace body 1 is provided with a variable diameter section, the variable diameter section includes a first contraction section, a smooth section and an expansion section, and the bottom end of the smoke exhaust outer pipe 24 is provided with a second contraction section, and the first contraction section is in parallel relationship with the second contraction section.

[0028] The bottom end outer wall of the flow guide cover 25 is in parallel relationship with the inner wall of the outer furnace body 1, and the top end annular outer wall of the outer furnace body 1 is in parallel relationship with the top end inner wall of the inner pipe 21.

[0029] The opening of the inner wall of the spray ring 23 corresponds to the inclined surface of the second contraction section up and down; The first gas film impacts the inclined surface of the second contraction section in the process of being sprayed vertically upward, is guided through the inclined surface of the second contraction section, and is guided into the spiral space formed by the first spiral threads 211, the second spiral threads 241, the outer wall of the inner pipe 21 and the inner wall of the smoke exhaust outer pipe 24.

[0030] Referring to Figures 1-9 In the embodiment, the top end outer wall of the smoke exhaust outer pipe 24 is provided with a flange plate, and the top end outer diameter of the smoke exhaust outer pipe 24 is greater than the top end outer diameter of the outer furnace body 1. The top end outer circle diameter of the smoke exhaust outer pipe 24 is larger than the top end outer circle diameter of the outer furnace body 1, which can prevent and block the upper opening of the first annular gap air channel, reduce the entry of dust and sundries into the first annular gap air channel to block the internal passage of the equipment, and reduce the failure rate of the equipment to a certain extent. At the same time, the flange plate arranged at the top end of the smoke exhaust outer pipe 24 is connected and fixed with the waste heat boiler, which is used to maximize the heat utilization rate.

[0031] The side outer wall of the bottom end of the outer furnace body 1 is obliquely and penetratingly provided with a smoke inlet section 11, which is communicated with the tail gas discharge port of the rotary kiln. The side outer wall of the bottom end of the outer furnace body 1 is provided with a slag removal opening 12. The slag removal opening 12 can be connected with a slag extractor to receive the ash and slag generated after incineration, and also can be used for cleaning personnel to enter the equipment to clean and maintain.

[0032] Working principle: first, the external gas supply equipment is connected and fixed with the flange plate of the air inlet ring pipe 22. After starting, high-pressure gas is injected into the air inlet ring pipe 22. Then the high-pressure gas is divided into two streams. One stream enters the spray ring 23 through the bifurcated pipe 221 and is vertically upwardly sprayed, closely flows along the inner wall of the smoke exhaust outer pipe 24, and forms a first gas film through the limitation of the inner wall of the smoke exhaust outer pipe 24 and the outer wall of the inner pipe 21, which can block the viscous adhesion of the adhesion on the inner wall of the smoke exhaust outer pipe 24, keep the inner wall of the smoke exhaust outer pipe 24 clean, and the high-speed and continuous gas film has a certain temperature insulation effect, which assists the refractory to insulate, reduces the heating degree of the refractory, prolongs the service life of the refractory to a certain extent, and reduces the cost of maintenance and replacement. Secondly, another high-pressure gas enters the ring wall gas channel through the bifurcated pipe 221, is impacted and dispersed into two annular gas flows by the flow guide cover 25, one of which is sprayed downward to form a second gas film in close contact with the inner wall of the outer furnace body 1, and the other is sprayed upward to form a third gas film in close contact with the inner wall of the inner pipe 21, the principle is as described above, the second gas film and the third gas film respectively protect the inner wall of the bottom of the outer furnace body 1 and the inner wall of the top of the inner pipe 21, and isolate the viscous adhesion, and the high-speed continuous gas film has a certain temperature insulation effect, which respectively reduces the influence of high temperature on the bottom of the outer furnace body 1 and the top of the inner pipe 21; at the same time, the burner on the flow guide cover 25 sprays flame jet to ignite the rising flue gas, and the heat sensing device cooperates to ensure that the flue gas is fully burned, the first gas film, the second gas film and the third gas film jointly increase the oxygen content in the equipment, which can promote the combustion to be more sufficient; then, the continuous injection of high-pressure gas increases the air pressure in the cavity below the inner pipe 21, and the gas flow sprays the flue gas in the combustion state along the inner wall of the flow guide cover 25 upward, under the influence of Bernoulli effect, the opening above the second annular gap will produce negative pressure, after the equipment runs for a period of time, the gas supply rate of the external gas supply equipment can be slowed down, only the auxiliary gas flow can be retained as the driving gas flow, the continuous flame jet maintains negative pressure above the second annular gap, and the connection structure of the ring pipe gas channel allows the external fresh air to be continuously sucked in, and when the fresh air travels to the bending part of the ring pipe gas channel, it is wrapped upward by the auxiliary gas flow, realizing gas self-circulation, reducing the energy consumption of the whole equipment, and reducing the operation cost; next, the first gas film sprays upward and impacts the inclined surface of the second contraction section at the bottom of the smoke exhaust outer pipe 24, enters the spiral space formed by the first spiral thread 211 and the second spiral thread 241 through the guide, forms a spiral gas flow, further adheres to the inner wall of the smoke exhaust outer pipe 24, and strengthens the isolation effect of the viscous adhesion, and the spiral gas film continuously maintains high speed, and the temperature insulation effect is more stable.

[0033] The technical scope of the present application is not limited to the content in the above description, and those skilled in the art can make various modifications and changes to the above embodiments without departing from the technical idea of the present application, and these modifications and changes should all belong to the protection scope of the present application.

Claims

1. A two-chamber multi-stage refractory lining structure for a rotary kiln hazardous waste incinerator, characterized by, The outer furnace body is internally fixed with a gas protection assembly for soft protection of the inner wall of the device by gas film; The gas protection assembly comprises an inner tube coaxially fixed to the inner wall of the outer furnace body, a plurality of sets of fixing blocks are arranged on the inner wall of the outer furnace body and above the inner tube to fixedly install an outer smoke exhaust pipe, the inner wall of the outer smoke exhaust pipe and the outer wall of the top tube of the inner tube jointly form a first annular gap air channel, the outer wall of the outer smoke exhaust pipe and the inner wall of the outer furnace body jointly form a second annular gap air channel, the first annular gap air channel and the second annular gap air channel are connected to form an annular pipe air channel, and a flow guide cover is fixed to the inner wall of the outer furnace body below the inner tube, the curved outer wall of the flow guide cover, the inner wall of the outer furnace body and the inner wall of the inner tube jointly form an annular wall air channel, and a spray ring is coaxially fixed to the lower surface of the outer smoke exhaust pipe at the joint of the first annular gap air channel and the second annular gap air channel. The inner tube is internally provided with a gas guide component for simultaneously supplementing high-pressure gas sources for the annular pipe air channel and the annular wall air channel.

2. A rotary kiln hazardous waste incineration two combustion chamber multi-stage refractory lining structure according to claim 1, characterized in that: The gas guide component comprises an air inlet annular pipe fixed to the outer wall of the outer furnace body, a plurality of sets of branch pipes are connected to the outer wall of the air inlet annular pipe near the shaft center at equal angles, and the branch pipes penetrate through the outer furnace body and extend into the inner tube.

3. A rotary kiln hazardous waste incineration two combustion chamber multi-stage refractory lining structure according to claim 2, characterized in that: One side port of the branch pipe is in communication with the inner cavity of the spray ring, the other side port of the branch pipe is in communication with the annular wall air channel, and the outer wall of the air inlet annular pipe is provided with an air inlet in communication with the output end of an external gas supply device.

4. A multi-stage refractory lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The inner wall cross section of the inner tube is funnel-shaped, and the outer diameter of the top spray port of the inner tube is smaller than the outer diameter of the outer smoke exhaust pipe.

5. A multi-stage refractory lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The outer wall of the inner tube is provided with a plurality of sets of first spiral threads at equal angles, the inner wall of the outer smoke exhaust pipe is provided with a plurality of sets of second spiral threads at equal angles, the first spiral threads and the second spiral threads are interpenetrated and staggered, and the outer wall of the top tube of the inner tube is in parallel relationship with the inner wall of the outer smoke exhaust pipe.

6. A multi-stage refractory lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The top outer wall of the outer furnace body is provided with a variable diameter section, the variable diameter section comprises a first contraction section, a smooth section and an expansion section, the bottom end of the outer smoke exhaust pipe is provided with a second contraction section, and the first contraction section is in parallel relationship with the second contraction section.

7. A multi-stage fire resistant lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The bottom outer wall of the flow guide cover is in parallel relationship with the inner wall of the outer furnace body, and the top annular outer wall of the outer furnace body is in parallel relationship with the top inner wall of the inner tube.

8. A multi-stage refractory lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The opening of the inner wall of the spray ring corresponds to the inclined surface of the second contraction section.

9. A multi-stage refractory lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The top outer wall of the outer smoke exhaust pipe is provided with a flange, and the top outer diameter of the outer smoke exhaust pipe is larger than the top outer diameter of the outer furnace body.

10. A multi-stage refractory lining structure for a secondary combustion chamber of a rotary kiln for hazardous waste incineration according to claim 1, characterized in that: The outer wall of one side of the bottom end of the outer furnace body is obliquely and interpenetratingly provided with a smoke inlet section, and the outer wall of one side of the bottom end of the outer furnace body is provided with a slag removal opening.

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